not all 2.5Gb switches from TP-Link are the same

[xorkon]

I purchased the TP-Link TL-SG105-M2, a 5 Port Multi-Gigabit(2.5G) Unmanaged Network Switch back in June os 2023 after owning its bigger brother TP-Link TL-SG108-M2, the 8 Port model over a year ago and really enjoyed it. Then in August I was able to get the China version of TP-Link's 5 Port 2.5G switch, model TL-SH1005, and it was a lot smaller than the US version, and similar in size too most of the cheap 2.5G switches on Amazon. I was going to use a pair of the China ones at home since I got Google Fiber, but quickly ran into two issues, 1st, the Chinese model overheats, and more importantly, I was having insane lag at random while gaming. I fixed the overheating issue by modding and replacing the tiny ceramic heatsink (20mmx20mmx8mm) with proper size aluminum heatsink, but I still get insane and random lags and high pings while gaming on any PCs connected to the switch. I change it out to the US version switch and everything is good, no lag, no high pings, no drops, and no overheating. The China version is powered by Realtek RTL8371, not sure what the US version uses, but I assume it is something similar, if anyone knows I would love if you share that info.

What I want to know is, why does the US version work fine without any issues, but the China version would have unstable behaviors with pings and connection in general. Is it a firmware thing? Not sure how I can even update firmware of an unmanaged switch, or if an updated firmware exists out there for it. Hopefully someone here knows.

 

[DavidWJohnston]

The packet loss problem may be the transceivers overheating, not the switch silicon itself. As a test, run it with the cover off with a fan above the transceiver cages and see if that fixes it.

 

[xorkon]

Thanks for the reply @DavidWJohnston , which part of the board are the transceivers? I attached a photo with the heatsink removed from the switch silicon.

 

[xorkon]

The transceiver is RTL8221B, I ordered some small heatsinks to try on them, will see if that fixes the issue and posts back

 

[zedalert]

I have had a similar issue with two 2.5GbE USB NICs based on Realtek - they have a good aluminium case, but a huge air gap between that case and transceiver. After a minute working at the maximum speed while transferring files from NAS it overheats and starts to drop speed and packets. So I glued up some threaded nuts to fill this gap, now this thing uses a whole metal case as a radiator, even after half an hour of files transfer at 280MBytes/s it doesn't overheat.

 

[xorkon]

The packet loss problem may be the transceivers overheating, not the switch silicon itself. As a test, run it with the cover off with a fan above the transceiver cages and see if that fixes it.

I modded the TL-SH1005 by replacing the small ceramic heatsink on the RTL8371 main silicon with a much larger aluminum heatsink and added heatsinks to all the RTL8221B transceiver chips (photos), but it did not resolve the latency issues. I also opened up the TL-SG105-M2 to see what is different in the US version compared to the Chinese version, ato my surprise the US version (TL-SG105-M2) is a lot simpler and without the latency issues that the Chinese version (TL-SH1005) causes. The US version only has 1 visible RTL8221B transceiver where as the China version has 5 separate ones. It could be that the US version heatsink is covering some but I am not sure. China version make use of 5 SQ24701 G LAN transformers, one per port, where as the US version uses 1 of them for the 5th port and 2 of the DQ48201 G LAN transformers which handles two ports each.

 

[fta]

Are these aliexpress switches actually tp-link brand or counterfeits?

 

[xorkon]

Are these aliexpress switches actually tp-link brand or counterfeits?

the TL-SH1005 ( TL-SH1005 2.5G以太网交换机 - TP-LINK官方网站 ) and the TL-SG105-M2 ( 5-Port 2.5G Desktop Switch )are both authentic TP-Link models, TL-SH1005 was ordered directly from an authorized distributor of TP-Link China, and TL-SG105-M2 was purchased from Amazon (ship and sold by Amazon). I try to stay away from aliexpress

 

[das1996]

@DavidWJohnston Are you familiar with the chineese offbrand 2.5gb+10gb switches. Like those in this thread - https://forums.servethehome.com/index.php?threads/horaco-2-5gbe-managed-switch.41571/

These do not appear to use a separate transceiver chip - built into the soc itself? What is the function of this chip?

http://imgur.com/Y5JN83Y

 

[DavidWJohnston]

Yeah I run one similar to this with 8x 10G SFP+. It works well.

The SQ24701 are isolation transformers, to improve signal quality.

The two chips under the heat sinks are the switch SoCs. It appears each one on the right does ports 1-4, and the left does 5-8 + the SFP+ port, and the chips are connected together.

I don't know if both SoCs are the same, or if one is a master and the other is an extension.

To support 10G over copper separate transceiver chips are probably needed - While at 2.5G it can be handled on the SoC.

 

[das1996]

I see, so these newer 8+1 type switches are theoretically more efficient because there's less hardware involved for the same functionality.

I only have a few 2.5gb clients, but have done continuous iperf testing for 30min+ without any meltdowns.

 

[up-n-atom]

The TP-LINK equivalent to the AliExpress managed special using the RTL8373+RTL8224 is the TL-SE2109PB and if you're interested in a teardown https://www.acwifi.net/25582.html